Vehicle wheel aligners are well known in the art. Such aligners typically comprise a computer or processor operated in conjunction with a number of alignment heads, mountable relative to the wheels of a vehicle, and angle measuring instruments to measure the alignment characteristics of the vehicle. Examples of such vehicle wheel aligners can be found in U.S. Pat. Nos. 5,724,743 and 5,875,418, both of which are owned by the assignee hereof. The alignment heads of these vehicle wheel aligners are typically mounted to the rims of the wheels using wheel clamps. Examples of such wheel clamps can be found in U.S. Pat. Nos. 5,242,202 issued to Ettinger; 4,815,216 issued to Swayne; and 4,285,136 issued to Ragan, all of which are owned by the assignee hereof.
These conventional vehicle wheel aligners are capable of indicating the adjustments that must be performed to correct wheel misalignment. For example, the vehicle wheel aligner might indicate that the camber, an angular measure representing the inward or outward tilt of the wheel from a true vertical, is 1.degree. and should be adjusted 1/2.degree. to a final value of 1/2.degree.. Likewise, the vehicle wheel aligner might indicate that the caster, an angular measure determined by the relationship of the upper ball joint to the lower ball joint or the upper pivot to the lower pivot in a forward and aft axis, which represents the forward or rearward tilt of the steering axis from a true vertical, is 2.degree. and should be adjusted 1.degree. to a final value of 1.degree..
However, access to the wheel alignment adjustment points to correct for the indicated deviations is often limited or restricted and it has therefore sometimes been necessary to remove the wheels and the alignment equipment, such as the alignment heads, to provide access to the wheel alignment adjustment points. This is evident, for example, in FIG. 1, which shows a cut-away view of a wheel (not numbered) mounted on a first configuration of vehicle suspension system components including a steering knuckle 10 of a spindle 20 movably attached to upper ball joint 12 and lower ball joint 14, joining the spindle to the upper control arm 16 and the lower control arm 18, respectively, as well as an upper control arm attachment 24. FIG. 2 shows a top view of a another configuration of vehicle suspension system components exposing the general relationship between a wheel 28 attached to a wheel mounting structure of a vehicle, an upper control arm 26, vehicle suspension adjustment points 30, and the vehicle frame 40. Vehicle suspension adjustment points 30 can be adjusted, such as by shimpacks (not numbered) installed at the adjustment points 30 to displace the upper control arm laterally from the vehicle frame 40. FIG. 3a is a top view of a third configuration of vehicle suspension system components including an asymmetric control arm 50 attached to a spindle 52 and a wheel 54. FIG. 3a illustrates, for this asymmetric control arm 50, an adjustment point 60, for adjusting caster, and an adjustment point 70, for adjusting camber. FIG. 3b shows an isometric view of the asymmetric upper control arm of FIG. 3a, showing the same vehicle suspension adjustment points 60, 70 of FIG. 3a. Thus, as shown by these examples, in many vehicle configurations the presence of the wheel impedes or prevents access to these, and other, adjustment points.
One conventional approach to access the vehicle suspension adjustment points involves removing the wheel alignment equipment and wheel following an initial reading, approximating the degree of the adjustment needed, executing the corresponding adjustments, reassembling of the wheel and measurement device, and remeasuring the alignment to determine if the adjustments are acceptable. However, this method is inexact and sometimes requires multiple iterations, involving considerable time.
In another conventional approach, alignment technicians remove the electronic measuring device and the wheel and substitute mechanical measuring devices, such as a level vial, to the hub to provide a visual indication of the degree of change. However, mechanical measuring devices are not as accurate as the electronic measuring device and, in the case of the level vial, the mechanical device is not suited for adjustments to caster.
In yet another conventional approach, alignment technicians simply leave the vehicle wheel alignment equipment in place and rely upon specialized tools, such as wrenches with particularized shapes and special pry bars, to compensate for the inaccessibility of the adjustment points. However, this approach requires a large inventory of specialized tools.
A need exists for an improved method of adjusting wheel alignment angles that provides enhanced access to wheel alignment adjustment points.